Recently, Yunnan has entered the rainy season, and the drought has been alleviated to some extent. The drought some time ago was due to the large-scale planting of the following fast-growing eucalyptus: 1. Fast-growing eucalyptus is a "water pump", which has a great demand for soil moisture. Large-scale planting will lead to the decline of groundwater level, poor water retention capacity, surface hardening and land desertification. It is reported that a large number of fast-growing eucalyptus trees were planted in Chini Town, Huadu District, Guangzhou 10 years ago. 10 years later, the streams flowing among trees dried up one after another, and the wells at the foot of the mountain became deeper and deeper; In some villages, once sweet springs have become bitter. 2. Fast-growing eucalyptus is a "fertilizer extractor". Fast-growing eucalyptus has a great demand for fertilizers and nutrients in the soil. Where fast-growing eucalyptus is planted, the soil fertility declines or even dries up, and the original vegetation is seriously damaged because it can't get enough fertilizer and nutrients, which leads to land degradation, soil and water conservation deterioration and barren land. It is impossible to survive if other plants are introduced and planted in the future. The proportion of soil strength erosion has increased year by year, and landslides and floods have increased. 3. Fast-growing eucalyptus is a "overlord tree". Fast-growing eucalyptus has a great inhibitory effect on local indigenous and protozoan species. When it grows, other species will slowly shrink, resulting in the bare surface of the fast-growing eucalyptus plantation, and there are no grasses, shrubs, young trees and various Chinese herbal medicines on the ground. Animals in the fast-growing eucalyptus forest are very rare or even extinct, the level of biodiversity is extremely low, the biological food chain is broken, and the ecology is very fragile. Without natural enemies to control pests, it is easy to suffer from insect disasters and lead to serious ecological crises such as microclimate change. Source: (/s/blog _ 621a135f0100hn80.html)-Cause analysis of drought in Yunnan _ Latent map _ Sina Blog4. The chemical products applied to fast-growing eucalyptus are highly toxic and have a long toxic action time. When planting fast-growing eucalyptus, apply some chemical products with long toxic effect. In addition, once the product is applied to the land, the smell of fast-growing eucalyptus has irritating and toxic effects on the human body. Although there are still different opinions on whether fast-growing eucalyptus is harmful to the ecological environment, it is certain that there are potential dangers in developing fast-growing eucalyptus on a large scale. The rapid development of newspaper industry has destroyed the original ecological environment in Yunnan. However, this is only an external reason. It has something to do with the local government's environmental protection system. To develop local economy, we should consider sustainable development, not just for immediate economic benefits. In our neighboring country, Japan, in order to protect the natural ecological environment, especially biodiversity, the Japanese government prohibits the planting of fast-growing and high-yield forests with single tree species that consume soil and water nutrients! Some eucalyptus chips used in their papermaking are imported from China.
In a research report written by Xu Jianchu, it is said that in recent years, extreme weather events and their serious disasters have increased on a global scale. According to statistics, in the 1990s, the number of major meteorological disasters in the world increased five times compared with that in the 1950s. Xu Jianchu said that the frequent occurrence of extreme weather events had something to do with the background of global warming. The scenarios analyzed and simulated by scientists using large computers show that climate warming will lead to the increase of many extreme weather and climate events. Almost all the land is very likely to have hot weather and heat waves increase; The value and frequency of extreme precipitation in many areas may also rise. The Influence of Three Monsoon Climate Yunnan is a transitional cross zone affected by various monsoons (East Asian Monsoon, South Asian Monsoon and Plateau Monsoon), and it is a typical monsoon climate zone in China. In addition, since June 2009, the equatorial Middle East Pacific Ocean has been unusually warm, and a new "El Ni? o" event has occurred, which has caused abnormal atmospheric circulation, and it is difficult for the cold air in the north to affect Yunnan southward. The warm and humid airflow from the southwest of the Indian Ocean is weak, resulting in insufficient water vapor supply. Coupled with the special geographical location of Yunnan's own low latitude plateau, it led to the continuous drought last winter and this spring.